I/O assistant blocked when using in a VI

[ghiocel]

I have an Agilent GPIB and an instrument equiped by a IEEE488 (16 bit)card.I try to use the I/O Assistant to communicate to the instrument. Inside the I/O Assistant I can execute the sequence step by step, and the results are correct, but when I try to use the configured I/O Assistant in a VI it does not work (it looks like the execution is blocked). I mention that I have a french version of LabView 7.0 (I red in one of the messages that this could be important, although I did not understad why).
Could someone please help me!!!
Angela

[TommyTestBoy]

Angela,

A few questions:

1.) When you say it "looks like execution is blocked", do you mean that the VI is sitting there executing the Express VI but never finishes? If this is the case, you can debug what is going on a bit more by right clicking on the Express VI and selecting "Show Front Panel" to see the LabVIEW code underneath.
2.) You mentioned you are using a French version of LabVIEW, are you also on a French Operating System? If you open the Express VI by selecting "Show Front Panel" on it, is the VI empty? Or is there code there?
3.) If you go to your \MAX\Assistants\ directory and find the file named IIOA.mxw, can you tell me what version the file is by looking at the file's properties?

-Tommy

[ghiocel]

Hello Tommy,
Thank you.
Here are the answers to your questions
1) Yes, it looks like it never finishes. I tried to debug it by clicking on "show front panel". The GPIB functions (read and write) give an error code 0.
2) The operating System is French too (Windows XP)
3) The version of IIOA.mxw is 3.0.1.3005
Angela

[TommyTestBoy]

Hmmm... if it is returning an error value of 0, then that means the GPIB functions are completing. If you turn on execution highlighting (by pressing the light bulb button in the toolbar of your VI), and run your VI, you should be able to tell where it is hung up in the code (like in an infinite loop somewhere, or inside of another VI or GPIB call). Does that give you any more information?

Can you post the VI with the generated I/O Assistant code here so I can look at it and see what is happening? Can you tell me what kind of instrument (manufacturer/model) you are trying to communicate with?

-Tommy

[ghiocel]

If I turn on the execution highlighting, it shows that GPIB call is executed and gives an error value 0. When I am using VISA calls the error is -1073807339 i.e. time out error. About the error value 0: that's also what I thought that it is not a real error, I also tried to de-wire the error codes, but it reads nothing on the interface.
The manufacturer name is jfa electronique and the model is ALBP602OIEEE.
I posted the I/O assistant.
Thank you for trying to help me
Angela

[ghiocel]

Hello
I have managed to solve the problem. Actually to bypass it. I have used the serial interface and it works.
Thanks a lot
Angela

[TommyTestBoy]

Angela,

Thanks. I was hoping it would be an instrument I was familiar with so I could try to debug what was happening - unfortunately, I am still unable to tell what is happening. Let me ask a couple more questions.

If the GPIB Read calls are returning 0 for an error, where is the hang? Does the loop that contains the GPIB Read continue to execute because the stop conditions are never met? Or is there a hang within a GPIB/VISA call?

I do not understand why the VISA code would time out, but the GPIB code would not. Another helpful bit of information would be an NI-SPY log. Are you familiar with NI-SPY? Can you post a log taken while running this VI?

The timeout in VISA code makes me worry that the generated code does not have the right address string or something. When you open the Express VI and view the generated code, does the ResourceName passed into the VISA/GPIB functions look correct?

-Tommy

[TommyTestBoy]

Angela,

Good - rarely has the answer been to use the serial interface instead of GPIB. 🙂 Good luck and let us know if you run into any more problems.

-Tommy